1. Field of the Invention
The present invention relates to a microfluidic device which controls a fluid movement and a microfluidic system comprising the same, and more particularly, to a microfluidic device employing a fluid movement using centrifugal force and a fluid movement using a pump, and a microfluidic system comprising the same.
2. Description of the Related Art
A microfluidic device includes a chamber which stores a minute amount of fluid, a channel through which the fluid flows and a valve which controls fluid flow. A biochip is formed by arranging such microfluidic devices on a chip-type substrate and is used to analyze a performance of various assays, including biological reactions. Particularly, a device that is designed to perform multiple step processes and manipulations using a single chip is called a lab-on-a chip (“LOC”).
A driving pressure is generally required in order to transfer the fluid within a microfluidic device. A capillary pressure or a pressure generated by a specifically prepared pump is used as the driving pressure. A lab compact disk (“CD”) is a recently introduced microfluidic device which is formed by arranging microfluidic structures on a compact disk-shaped platform and which uses centrifugal force. In a case of a microfluidic device using centrifugal force to control a fluid movement, the fluid movement is limited to an outward direction from a rotation shaft. Therefore, a chamber where a fluid movement starts, such as a sample chamber, should be disposed at a portion of the microfluidic device proximate to the rotation shaft. However, it is difficult to obtain an area close to the rotation shaft for mounting chamber structures having a large volume because the portion of the microfluidic device proximate to the rotation shaft has a relatively small area, as compared to a portion further away from the rotation shaft. Also, a rotation speed of the microfluidic device should be limited such that a valve can resist the rotation of the microfluidic device or such that a channel can serve as a valve during a fluid movement.
In a case of the microfluidic device using a pump to move a fluid, it is difficult to collect a solution which remains between pillars or beads by using a capillary force in a trap chamber which includes a plurality of pillar structures or packed beads.